Switching systems are used to provide telecommunications services between two or more user interfaces. User interfaces may include telephone handsets, facsimile machines, computers, and other equipment, and may be connected to the switching system by fixed land-based conductors or wireless services. Telecommunications services are provided by establishing a telecommunications channel between two user interfaces, such that encoded analog or digital data may be transmitted between the user interfaces until a state of completion is reached.
An undesired characteristic of telecommunications channels is the generation of echo signals. Echo signals may be inadvertently created, and are usually a function of the physical parameters of the telecommunications channel. The echo signals can disrupt voice and data communications, thus diminishing the commercial value of the telecommunications channel. Echo cancellation circuits are routinely used to prevent echo signals from degrading telecommunications channels.
Echo cancellation circuits typically use an echo cancellation algorithm that includes several variables that may be adjusted for each circuit in order to optimize the effectiveness of echo cancellation. When a wireless telecommunications user moves from a first communications cell to a second communications cell, it may be necessary to transfer the telecommunications channel from a first echo cancellation circuit to a second echo cancellation circuit. As a result of the transfer, the new echo cancellation circuit must adjust the echo cancellation algorithm variables in response to the physical parameters of the telecommunications channel. The echo cancellation algorithm variable adjustment process can result in degraded telecommunications quality and unwanted signal generation for a significant period of time, potentially causing user discomfort, loss of data, or resetting of the data channel with a corresponding loss of the call.